That might be the best-case scenario the 8-7 Dallas Cowboys can hope for from the respected veteran backup quarterback, who – with Tony Romo sidelined by a season-ending herniated disk – will start Sunday night's win-or-go-home NFC East title game against the 9-6 Philadelphia Eagles.

Heck, it is not as if Romo has lit it up in elimination game situations, going 1-6 in either winner-take-all games to end the regular season or the playoffs (1-3).

"This is the same situation the Chicago Bears had with Josh McCown stepping in this season for an injured Jay Cutler, a cavalier quarterback just like Tony Romo,'' former Bears quarterback and current analyst Jim Miller told USA TODAY Sports. "Josh came in when Jay went down with groin and ankle injuries and the offense ran efficiently.

"For Dallas, that's how it will be with Kyle Orton. He's one of the league's better backups who will run that offense efficiently."

Miller acknowledged though, that it's not an easy assignment to keep pace with the explosive Eagles.

"Yeah, this puts Kyle in a tough spot. But guys love playing with him whether it was in Chicago, Denver or Kansas City. They respect his leadership," Miller said. "He knows he has to score a lot of points with that defense. He'll get you in the right play pre-snap and he's accurate as all can be.''

McCown provided strong, poised play in going 3-2 for the Bears, throwing 13 touchdowns with one interception in posting the league's third-highest passer rating of 109 during the five starts he replaced Cutler.

Best known of late as the guy who in 2011 was benched for Tim Tebow during his magical but short-lived playoff run in Denver, Orton, 31, is respected as a strong-armed pocket passer.

Orton owns a 35-34 career starting record though he has thrown just 15 passes since he last started and won the 2011 regular-season finale for the Kansas City Chiefs.

The 6-4, 228-pound Orton lacks Romo's signature escapability when the pocket crumbles. But Orton, who signed a three-year, $10.5 million deal in March 2012, is known for cycling quickly through his progressions while throwing with good anticipation and accuracy.

"We have Kyle Orton here for a reason,'' Cowboys coach Jason Garrett said Monday. "He's a veteran quarterback who has started (69) games in the NFL. So he understands what his role is each and every week in terms of preparation.

"Kyle knows that he has to be ready. Kyle prepares as if he's the starting quarterback each week.''

Romo was limping noticeably before throwing the winning, 10-yard touchdown pass to DeMarco Murray on fourth-and-goal. He'd already aggravated a herniated disk in his back, ending his season, a person with knowledge of the injury told USA TODAY Sports.

The person spoke on condition of anonymity because the medical details were to remain confidential. Cowboys owner Jerry Jones did say in a radio interview that Romo had not yet been ruled out, but most expected he would not be on the field.

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Can Orton change the narrative on the Cowboys' late-season meltdowns and return them to the playoffs for the first time since 2009?

"Kyle has the experience as a starter – so it's not like he's some wide-eyed rookie who is going to crumble under the pressure,'' said Rich Gannon, the former Oakland Raider and league MVP. "One of the problems could be with his precision since it's been a while since he's played.

"He doesn't move as well as Tony outside the pocket, but he has the arm talent and can make all the throws.''

The Cowboys can take some solace in the fact that Minnesota Vikings backup Matt Cassel lit up the Eagles 30th-ranked passing defense for 382 yards, two touchdowns with an interception in completing 74.2% of his passes in a 48-30 Dec. 15 win.

But the Eagles rebounded with a 54-11 rout of the Bears and have won six of their last seven games led by quarterback Nick Foles, the league's highest-rated passer who has thrown 25 touchdowns with two interceptions.

What's more, Orton must cover for a historically porous Cowboys defense that is allowing 27.8 points and 418.6 yards per game.

"Dallas can't stop anybody,'' said Gannon, a CBS analyst. "I remember (former Raiders coach) Jon Gruden saying to me on a Saturday night as we were going through the final game plan, 'Hey, listen, you're going to have to go out and score 35 points for us to have a chance to go win.'

"That's where the Cowboys are right now with as bad as that defense is."

The Cowboys are not catching the Eagles at a good time, even if Dallas is the home team, Gannon said.

"Philly is the more confident team," he said. "Regardless of whether Orton or Romo plays, the result will be similar.''